Syrian militia launches offensive to capture Raqqa

June 6 (UPI) -- The U.S.-led international coalition said the Syrian Democratic Forces militia launched a ground offensive to capture the Islamic State's stronghold of Raqqa, the U.S. military said.

The SDF's offensive began on Tuesday after efforts to capture the city's surrounding territory began in November.

The U.S.-led anti-Islamic State international coalition called the Combined Joint Task Force: Operation Inherent Resolve said the SDF has been "rapidly tightening the noose around the city since their daring air assault behind enemy lines in coalition aircraft in March to begin the seizure of Tabqah."

U.S. Army Lt. Gen. Stephen J. Townsend, commanding general of the coalition, said the fight for Raqqa will be long and difficult, but victory will deliver a decisive blow to the idea of the Islamic State as a physical, ruling entity.

The offensive in Raqqa comes as Iraqi security forces near victory in west Mosul, though progress has been slow in the densely populated areas of Iraq's second-largest city. The SDF's assault also follows the attacks in London and Manchester for which the Islamic State, also known as ISIL, Daesh, and ISIS, took credit.

"It's hard to convince new recruits that ISIS is a winning cause when they just lost their twin 'capitals' in both Iraq and Syria," Townsend said in a statement. "We all saw the heinous attack in Manchester, England. ISIS threatens all of our nations, not just Iraq and Syria, but in our own homelands as well. This cannot stand."

The SDF has called on Raqqa residents to evacuate so they do not become trapped, are not killed by Islamic State snipers and are not used as human shields

The U.S.-led coalition supports the SDF by providing equipment, training, intelligence and logistics support, airstrikes and battlefield advice.